The manner in which a biological tissue sample is to be prepared for histological investigation is known. Firstly the tissue sample is cut to size and introduced into a cassette. The sample is then prepared, using a plurality of chemical treatments, for microscopic investigation. In the context of chemical treatment, firstly the sample is fixed with a fixing medium, the water present in the sample is removed, and optionally further processing steps are completed. At the end of this multi-step process is infiltration of an infiltration medium, usually paraffin, into the sample. The sample is then embedded, usually manually, into an embedding medium, usually paraffin, by means of a molding operation, and the embedded block is connected to the cassette. The cassette serves as a carrier that can be introduced into a corresponding receptacle of a microtome and fastened there.
The result is an embedded block with cassette in which the sample is secured in stationary fashion. After hardening of the embedding medium, the sample can be sectioned with the microtome into individual thin sample sections that, in a subsequent step, can be stained and investigated with a microscope.
EP 2 322 938 B1 discloses an automated machine that is embodied to embed tissue samples onto very special carriers, namely those which are suitable for being sectioned with a microtome together with the embedded sample. The machine comprises multiple immovable holders, each holder being embodied to hold one of the special carriers during the entire embedding operation. Once a carrier filled with a sample has been positioned in a holder, the carrier is filled with an embedding medium that is delivered from a dispenser. The carrier is then cooled by the holder, which in order to implement an additional function is additionally embodied as a cooling unit. During the entire embedding process, each carrier remains in its position defined by the respective holder. The dispenser services all of the plurality of holders.
The concept on which this machine is based disadvantageously requires a complex and malfunction-prone configuration. This relates in particular to the dispenser, which must be able to reach each individual one of the holders so that paraffin heated to above its melting point can be distributed.